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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.document.select.convert;
import com.yahoo.document.select.NowCheckVisitor;
import com.yahoo.document.select.Visitor;
import com.yahoo.document.select.rule.ArithmeticNode;
import com.yahoo.document.select.rule.AttributeNode;
import com.yahoo.document.select.rule.ComparisonNode;
import com.yahoo.document.select.rule.DocumentNode;
import com.yahoo.document.select.rule.DocumentTypeNode;
import com.yahoo.document.select.rule.EmbracedNode;
import com.yahoo.document.select.rule.ExpressionNode;
import com.yahoo.document.select.rule.IdNode;
import com.yahoo.document.select.rule.LiteralNode;
import com.yahoo.document.select.rule.LogicNode;
import com.yahoo.document.select.rule.NegationNode;
import com.yahoo.document.select.rule.NowNode;
import com.yahoo.document.select.rule.VariableNode;
import java.util.HashMap;
import java.util.Map;
/**
* Class which converts a selection tree into a set of queries per document type.
* If unsupported operations are or illegal arguments are encountered, an exception is thrown.
*
* @author Ulf Lilleengen
*/
public class SelectionExpressionConverter implements Visitor {
private final Map<String, NowQueryExpression> expressionMap = new HashMap<>();
private static class BuildState {
public AttributeNode attribute;
public ComparisonNode comparison;
public ArithmeticNode arithmetic;
public NowNode now;
}
private BuildState state;
private boolean hasNow(ExpressionNode node) {
NowCheckVisitor visitor = new NowCheckVisitor();
node.accept(visitor);
return visitor.requiresConversion();
}
public SelectionExpressionConverter() {
this.state = null;
}
public Map<String, String> getQueryMap() {
Map<String, String> ret = new HashMap<>();
for (NowQueryExpression expression : expressionMap.values()) {
ret.put(expression.getDocumentType(), expression.toString());
}
return ret;
}
public void visit(ArithmeticNode node) {
if (state == null ) return;
if (node.getItems().size() > 2) {
throw new IllegalArgumentException("Too many arithmetic operations");
}
for (ArithmeticNode.NodeItem item : node.getItems()) {
if (item.getOperator() != ArithmeticNode.SUB && item.getOperator() != ArithmeticNode.NOP) {
throw new IllegalArgumentException("Arithmetic operator '" + node.operatorToString(item.getOperator()) + "' is not supported");
}
}
state.arithmetic = node;
}
public void visit(AttributeNode node) {
if (state == null ) return;
if (expressionMap.containsKey(node.getValue().toString())) {
throw new IllegalArgumentException("Specifying multiple document types is not allowed");
}
for (AttributeNode.Item item : node.getItems()) {
if (item.getType() != AttributeNode.Item.ATTRIBUTE) {
throw new IllegalArgumentException("Only attribute items are supported");
}
}
state.attribute = node;
}
public void visit(ComparisonNode node) {
if (state != null) {
throw new IllegalArgumentException("Comparison cannot be done within now expression");
}
if (!hasNow(node)) {
return;
}
state = new BuildState();
node.getLHS().accept(this);
node.getRHS().accept(this);
if (!">".equals(node.getOperator())) {
throw new IllegalArgumentException("Comparison operator '" + node.getOperator() + "' is not supported");
}
if (!(node.getLHS() instanceof AttributeNode)) {
throw new IllegalArgumentException("Left hand side of comparison must be a document field");
}
state.comparison = node;
if (state.attribute != null &&
(state.arithmetic != null || state.now != null)) {
NowQueryExpression expression = new NowQueryExpression(state.attribute, state.comparison, state.arithmetic);
expressionMap.put(expression.getDocumentType(), expression);
state = null;
}
}
public void visit(DocumentNode node) {
// Silently ignore
}
public void visit(DocumentTypeNode node) {
// Silently ignore
}
public void visit(EmbracedNode node) {
if (state == null ) return;
throw new UnsupportedOperationException("Grouping is not supported yet.");
}
public void visit(IdNode node) {
if (state == null ) return;
throw new UnsupportedOperationException("Document id not supported yet.");
}
public void visit(LiteralNode node) {
if (state == null ) return;
if (!(node.getValue() instanceof Long)) {
throw new IllegalArgumentException("Literal " + node + " is not supported");
}
}
public void visit(LogicNode node) {
if (state != null) {
throw new IllegalArgumentException("Logic expressions not supported in now expressions");
}
for (LogicNode.NodeItem item : node.getItems()) {
item.getNode().accept(this);
}
}
public void visit(NegationNode node) {
if (state == null ) return;
throw new UnsupportedOperationException("Negation not supported yet.");
}
public void visit(NowNode node) {
if (state == null ) return;
state.now = node;
}
public void visit(VariableNode node) {
if (state == null ) return;
throw new UnsupportedOperationException("Variables not supported yet.");
}
}
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